Brake drum Temp

[prb51]

Replaced the rear brakes on my TR3 and adjusted as per the book.
After a 7 mile run at 55-70 and a stop from 70 MPH had a drum temp of 205 degrees.
What are normal op temps anyway for drums?

 

[TR3driver]

Depends greatly on how hard, and how recently, you've been using them. That does not seem excessive to me, assuming you checked them immediately. As long as they aren't dragging, I'd say you're good.

Besides, the heat indicates they are working (the function of brakes is to convert kinetic energy to heat). Other than dragging, about the only thing that could get them too hot was if the front brakes weren't working!
:laugh:

 

[prb51]

Hard to tell if they are dragging but if so it must only be slightly. Was just wondering about optimal op temps as I've never checked by temp before (laser temp gauge in hand).
I believe they don't 'smell' until about 500 degrees and smoke at 800...so a good op temp range would be 200 400 degrees when working them? For street drums only as I know discs run much hotter effectively.

 

[TomMull]

205 degrees F does not sound too unreasonable to me after a stop from 70 mph, although I've never measured the temp. I wouldn't worry much about the drum temperature as long as you are sure the heat is not from a dragging brake. You might try the same test except that you'd coast to a stop. They shouldn't be much above air temperature and both sides should be about the same. Or you could just jack up the back of the car and insure that both sides spin freely.
Tom

 

[Perrymip]

There is an unmistakable odor accompanying half-a-dozen miles at 70 mph with the linings pressing against the drums, if that's what you're thinking about. Those of us who have accidentally left the emergency brake partly engaged, and shot off toward the horizon, know that smell quite well.

 

[prb51]

Tom,
I have jacked them up etc but you have the weight of the wheel, pumpkin and drive shaft moving too and diff to feel a slight drag.

I've never tested using a temp gauge (laser) so was just wondering. I know they 'smell' at 500 d and smoke at 800 d so am guessing a good op temp range for working them would be 200-400 degrees. Just a swag.

 

[TR3driver]

Those of us who have accidentally left the emergency brake partly engaged, and shot off toward the horizon, know that smell quite well.

Not to mention the smoke.

Although in my case, it was a failed brake hose holding them on.